import platform

import numpy as np
from numpy import uint16, float16, float32, float64
from numpy.testing import TestCase, run_module_suite, assert_, assert_equal, \
    dec


def assert_raises_fpe(strmatch, callable, *args, **kwargs):
    try:
        callable(*args, **kwargs)
    except FloatingPointError as exc:
        assert_(str(exc).find(strmatch) >= 0,
                "Did not raise floating point %s error" % strmatch)
    else:
        assert_(False,
                "Did not raise floating point %s error" % strmatch)

class TestHalf(TestCase):
    def setUp(self):
        # An array of all possible float16 values
        self.all_f16 = np.arange(0x10000, dtype=uint16)
        self.all_f16.dtype = float16
        self.all_f32 = np.array(self.all_f16, dtype=float32)
        self.all_f64 = np.array(self.all_f16, dtype=float64)

        # An array of all non-NaN float16 values, in sorted order
        self.nonan_f16 = np.concatenate(
                                    (np.arange(0xfc00,0x7fff,-1, dtype=uint16),
                                     np.arange(0x0000,0x7c01,1, dtype=uint16))
                                    )
        self.nonan_f16.dtype = float16
        self.nonan_f32 = np.array(self.nonan_f16, dtype=float32)
        self.nonan_f64 = np.array(self.nonan_f16, dtype=float64)

        # An array of all finite float16 values, in sorted order
        self.finite_f16 = self.nonan_f16[1:-1]
        self.finite_f32 = self.nonan_f32[1:-1]
        self.finite_f64 = self.nonan_f64[1:-1]

    def test_half_conversions(self):
        """Checks that all 16-bit values survive conversion
           to/from 32-bit and 64-bit float"""
        # Because the underlying routines preserve the NaN bits, every
        # value is preserved when converting to/from other floats.

        # Convert from float32 back to float16
        b = np.array(self.all_f32, dtype=float16)
        assert_equal(self.all_f16.view(dtype=uint16),
                     b.view(dtype=uint16))

        # Convert from float64 back to float16
        b = np.array(self.all_f64, dtype=float16)
        assert_equal(self.all_f16.view(dtype=uint16),
                     b.view(dtype=uint16))

        # Convert float16 to longdouble and back
        # This doesn't necessarily preserve the extra NaN bits,
        # so exclude NaNs.
        a_ld = np.array(self.nonan_f16, dtype=np.longdouble)
        b = np.array(a_ld, dtype=float16)
        assert_equal(self.nonan_f16.view(dtype=uint16),
                     b.view(dtype=uint16))

        # Check the range for which all integers can be represented
        i_int = np.arange(-2048,2049)
        i_f16 = np.array(i_int, dtype=float16)
        j = np.array(i_f16, dtype=np.int)
        assert_equal(i_int,j)

    def test_nans_infs(self):
        oldsettings = np.seterr(all='ignore')
        try:
            # Check some of the ufuncs
            assert_equal(np.isnan(self.all_f16), np.isnan(self.all_f32))
            assert_equal(np.isinf(self.all_f16), np.isinf(self.all_f32))
            assert_equal(np.isfinite(self.all_f16), np.isfinite(self.all_f32))
            assert_equal(np.signbit(self.all_f16), np.signbit(self.all_f32))
            assert_equal(np.spacing(float16(65504)), np.inf)

            # Check comparisons of all values with NaN
            nan = float16(np.nan)

            assert_(not (self.all_f16 == nan).any())
            assert_(not (nan == self.all_f16).any())

            assert_((self.all_f16 != nan).all())
            assert_((nan != self.all_f16).all())

            assert_(not (self.all_f16 < nan).any())
            assert_(not (nan < self.all_f16).any())

            assert_(not (self.all_f16 <= nan).any())
            assert_(not (nan <= self.all_f16).any())

            assert_(not (self.all_f16 > nan).any())
            assert_(not (nan > self.all_f16).any())

            assert_(not (self.all_f16 >= nan).any())
            assert_(not (nan >= self.all_f16).any())
        finally:
            np.seterr(**oldsettings)


    def test_half_values(self):
        """Confirms a small number of known half values"""
        a = np.array([1.0, -1.0,
                      2.0, -2.0,
                      0.0999755859375, 0.333251953125, # 1/10, 1/3
                      65504, -65504,           # Maximum magnitude
                      2.0**(-14), -2.0**(-14), # Minimum normal
                      2.0**(-24), -2.0**(-24), # Minimum subnormal
                      0, -1/1e1000,            # Signed zeros
                      np.inf, -np.inf])
        b = np.array([0x3c00, 0xbc00,
                      0x4000, 0xc000,
                      0x2e66, 0x3555,
                      0x7bff, 0xfbff,
                      0x0400, 0x8400,
                      0x0001, 0x8001,
                      0x0000, 0x8000,
                      0x7c00, 0xfc00], dtype=uint16)
        b.dtype = float16
        assert_equal(a, b)

    def test_half_rounding(self):
        """Checks that rounding when converting to half is correct"""
        a = np.array([2.0**-25 + 2.0**-35,  # Rounds to minimum subnormal
                      2.0**-25,       # Underflows to zero (nearest even mode)
                      2.0**-26,       # Underflows to zero
                      1.0+2.0**-11 + 2.0**-16, # rounds to 1.0+2**(-10)
                      1.0+2.0**-11,   # rounds to 1.0 (nearest even mode)
                      1.0+2.0**-12,   # rounds to 1.0
                      65519,          # rounds to 65504
                      65520],         # rounds to inf
                      dtype=float64)
        rounded = [2.0**-24,
                   0.0,
                   0.0,
                   1.0+2.0**(-10),
                   1.0,
                   1.0,
                   65504,
                   np.inf]

        # Check float64->float16 rounding
        b = np.array(a, dtype=float16)
        assert_equal(b, rounded)

        # Check float32->float16 rounding
        a = np.array(a, dtype=float32)
        b = np.array(a, dtype=float16)
        assert_equal(b, rounded)

    def test_half_correctness(self):
        """Take every finite float16, and check the casting functions with
           a manual conversion."""

        # Create an array of all finite float16s
        a_f16 = self.finite_f16
        a_bits = a_f16.view(dtype=uint16)

        # Convert to 64-bit float manually
        a_sgn = (-1.0)**((a_bits&0x8000) >> 15)
        a_exp = np.array((a_bits&0x7c00) >> 10, dtype=np.int32) - 15
        a_man = (a_bits&0x03ff) * 2.0**(-10)
        # Implicit bit of normalized floats
        a_man[a_exp!=-15] += 1
        # Denormalized exponent is -14
        a_exp[a_exp==-15] = -14

        a_manual = a_sgn * a_man * 2.0**a_exp

        a32_fail = np.nonzero(self.finite_f32 != a_manual)[0]
        if len(a32_fail) != 0:
            bad_index = a32_fail[0]
            assert_equal(self.finite_f32, a_manual,
                 "First non-equal is half value %x -> %g != %g" %
                            (a[bad_index],
                             self.finite_f32[bad_index],
                             a_manual[bad_index]))

        a64_fail = np.nonzero(self.finite_f64 != a_manual)[0]
        if len(a64_fail) != 0:
            bad_index = a64_fail[0]
            assert_equal(self.finite_f64, a_manual,
                 "First non-equal is half value %x -> %g != %g" %
                            (a[bad_index],
                             self.finite_f64[bad_index],
                             a_manual[bad_index]))

    def test_half_ordering(self):
        """Make sure comparisons are working right"""

        # All non-NaN float16 values in reverse order
        a = self.nonan_f16[::-1].copy()

        # 32-bit float copy
        b = np.array(a, dtype=float32)

        # Should sort the same
        a.sort()
        b.sort()
        assert_equal(a, b)

        # Comparisons should work
        assert_((a[:-1] <= a[1:]).all())
        assert_(not (a[:-1] > a[1:]).any())
        assert_((a[1:] >= a[:-1]).all())
        assert_(not (a[1:] < a[:-1]).any())
        # All != except for +/-0
        assert_equal(np.nonzero(a[:-1] < a[1:])[0].size, a.size-2)
        assert_equal(np.nonzero(a[1:] > a[:-1])[0].size, a.size-2)

    def test_half_funcs(self):
        """Test the various ArrFuncs"""

        # fill
        assert_equal(np.arange(10, dtype=float16),
                     np.arange(10, dtype=float32))

        # fillwithscalar
        a = np.zeros((5,), dtype=float16)
        a.fill(1)
        assert_equal(a, np.ones((5,), dtype=float16))

        # nonzero and copyswap
        a = np.array([0,0,-1,-1/1e20,0,2.0**-24, 7.629e-6], dtype=float16)
        assert_equal(a.nonzero()[0],
                     [2,5,6])
        a = a.byteswap().newbyteorder()
        assert_equal(a.nonzero()[0],
                     [2,5,6])

        # dot
        a = np.arange(0, 10, 0.5, dtype=float16)
        b = np.ones((20,), dtype=float16)
        assert_equal(np.dot(a,b),
                     95)

        # argmax
        a = np.array([0, -np.inf, -2, 0.5, 12.55, 7.3, 2.1, 12.4], dtype=float16)
        assert_equal(a.argmax(),
                     4)
        a = np.array([0, -np.inf, -2, np.inf, 12.55, np.nan, 2.1, 12.4], dtype=float16)
        assert_equal(a.argmax(),
                     5)

        # getitem
        a = np.arange(10, dtype=float16)
        for i in range(10):
            assert_equal(a.item(i),i)

    def test_spacing_nextafter(self):
        """Test np.spacing and np.nextafter"""
        # All non-negative finite #'s
        a = np.arange(0x7c00, dtype=uint16)
        hinf = np.array((np.inf,), dtype=float16)
        a_f16 = a.view(dtype=float16)

        assert_equal(np.spacing(a_f16[:-1]), a_f16[1:]-a_f16[:-1])

        assert_equal(np.nextafter(a_f16[:-1], hinf), a_f16[1:])
        assert_equal(np.nextafter(a_f16[0], -hinf), -a_f16[1])
        assert_equal(np.nextafter(a_f16[1:], -hinf), a_f16[:-1])

        # switch to negatives
        a |= 0x8000

        assert_equal(np.spacing(a_f16[0]), np.spacing(a_f16[1]))
        assert_equal(np.spacing(a_f16[1:]), a_f16[:-1]-a_f16[1:])

        assert_equal(np.nextafter(a_f16[0], hinf), -a_f16[1])
        assert_equal(np.nextafter(a_f16[1:], hinf), a_f16[:-1])
        assert_equal(np.nextafter(a_f16[:-1], -hinf), a_f16[1:])


    def test_half_ufuncs(self):
        """Test the various ufuncs"""

        a = np.array([0,1,2,4,2], dtype=float16)
        b = np.array([-2,5,1,4,3], dtype=float16)
        c = np.array([0,-1,-np.inf,np.nan,6], dtype=float16)

        assert_equal(np.add(a,b), [-2,6,3,8,5])
        assert_equal(np.subtract(a,b), [2,-4,1,0,-1])
        assert_equal(np.multiply(a,b), [0,5,2,16,6])
        assert_equal(np.divide(a,b), [0,0.199951171875,2,1,0.66650390625])

        assert_equal(np.equal(a,b), [False,False,False,True,False])
        assert_equal(np.not_equal(a,b), [True,True,True,False,True])
        assert_equal(np.less(a,b), [False,True,False,False,True])
        assert_equal(np.less_equal(a,b), [False,True,False,True,True])
        assert_equal(np.greater(a,b), [True,False,True,False,False])
        assert_equal(np.greater_equal(a,b), [True,False,True,True,False])
        assert_equal(np.logical_and(a,b), [False,True,True,True,True])
        assert_equal(np.logical_or(a,b), [True,True,True,True,True])
        assert_equal(np.logical_xor(a,b), [True,False,False,False,False])
        assert_equal(np.logical_not(a), [True,False,False,False,False])

        assert_equal(np.isnan(c), [False,False,False,True,False])
        assert_equal(np.isinf(c), [False,False,True,False,False])
        assert_equal(np.isfinite(c), [True,True,False,False,True])
        assert_equal(np.signbit(b), [True,False,False,False,False])

        assert_equal(np.copysign(b,a), [2,5,1,4,3])

        assert_equal(np.maximum(a,b), [0,5,2,4,3])
        x = np.maximum(b,c)
        assert_(np.isnan(x[3]))
        x[3] = 0
        assert_equal(x, [0,5,1,0,6])
        assert_equal(np.minimum(a,b), [-2,1,1,4,2])
        x = np.minimum(b,c)
        assert_(np.isnan(x[3]))
        x[3] = 0
        assert_equal(x, [-2,-1,-np.inf,0,3])
        assert_equal(np.fmax(a,b), [0,5,2,4,3])
        assert_equal(np.fmax(b,c), [0,5,1,4,6])
        assert_equal(np.fmin(a,b), [-2,1,1,4,2])
        assert_equal(np.fmin(b,c), [-2,-1,-np.inf,4,3])

        assert_equal(np.floor_divide(a,b), [0,0,2,1,0])
        assert_equal(np.remainder(a,b), [0,1,0,0,2])
        assert_equal(np.square(b), [4,25,1,16,9])
        assert_equal(np.reciprocal(b), [-0.5,0.199951171875,1,0.25,0.333251953125])
        assert_equal(np.ones_like(b), [1,1,1,1,1])
        assert_equal(np.conjugate(b), b)
        assert_equal(np.absolute(b), [2,5,1,4,3])
        assert_equal(np.negative(b), [2,-5,-1,-4,-3])
        assert_equal(np.sign(b), [-1,1,1,1,1])
        assert_equal(np.modf(b), ([0,0,0,0,0],b))
        assert_equal(np.frexp(b), ([-0.5,0.625,0.5,0.5,0.75],[2,3,1,3,2]))
        assert_equal(np.ldexp(b,[0,1,2,4,2]), [-2,10,4,64,12])

    def test_half_coercion(self):
        """Test that half gets coerced properly with the other types"""
        a16 = np.array((1,),dtype=float16)
        a32 = np.array((1,),dtype=float32)
        b16 = float16(1)
        b32 = float32(1)

        assert_equal(np.power(a16,2).dtype, float16)
        assert_equal(np.power(a16,2.0).dtype, float16)
        assert_equal(np.power(a16,b16).dtype, float16)
        assert_equal(np.power(a16,b32).dtype, float16)
        assert_equal(np.power(a16,a16).dtype, float16)
        assert_equal(np.power(a16,a32).dtype, float32)

        assert_equal(np.power(b16,2).dtype, float64)
        assert_equal(np.power(b16,2.0).dtype, float64)
        assert_equal(np.power(b16,b16).dtype, float16)
        assert_equal(np.power(b16,b32).dtype, float32)
        assert_equal(np.power(b16,a16).dtype, float16)
        assert_equal(np.power(b16,a32).dtype, float32)

        assert_equal(np.power(a32,a16).dtype, float32)
        assert_equal(np.power(a32,b16).dtype, float32)
        assert_equal(np.power(b32,a16).dtype, float16)
        assert_equal(np.power(b32,b16).dtype, float32)

    @dec.skipif(platform.machine() == "armv5tel", "See gh-413.")
    def test_half_fpe(self):
        oldsettings = np.seterr(all='raise')
        try:
            sx16 = np.array((1e-4,),dtype=float16)
            bx16 = np.array((1e4,),dtype=float16)
            sy16 = float16(1e-4)
            by16 = float16(1e4)

            # Underflow errors
            assert_raises_fpe('underflow', lambda a,b:a*b, sx16, sx16)
            assert_raises_fpe('underflow', lambda a,b:a*b, sx16, sy16)
            assert_raises_fpe('underflow', lambda a,b:a*b, sy16, sx16)
            assert_raises_fpe('underflow', lambda a,b:a*b, sy16, sy16)
            assert_raises_fpe('underflow', lambda a,b:a/b, sx16, bx16)
            assert_raises_fpe('underflow', lambda a,b:a/b, sx16, by16)
            assert_raises_fpe('underflow', lambda a,b:a/b, sy16, bx16)
            assert_raises_fpe('underflow', lambda a,b:a/b, sy16, by16)
            assert_raises_fpe('underflow', lambda a,b:a/b,
                                             float16(2.**-14), float16(2**11))
            assert_raises_fpe('underflow', lambda a,b:a/b,
                                             float16(-2.**-14), float16(2**11))
            assert_raises_fpe('underflow', lambda a,b:a/b,
                                             float16(2.**-14+2**-24), float16(2))
            assert_raises_fpe('underflow', lambda a,b:a/b,
                                             float16(-2.**-14-2**-24), float16(2))
            assert_raises_fpe('underflow', lambda a,b:a/b,
                                             float16(2.**-14+2**-23), float16(4))

            # Overflow errors
            assert_raises_fpe('overflow', lambda a,b:a*b, bx16, bx16)
            assert_raises_fpe('overflow', lambda a,b:a*b, bx16, by16)
            assert_raises_fpe('overflow', lambda a,b:a*b, by16, bx16)
            assert_raises_fpe('overflow', lambda a,b:a*b, by16, by16)
            assert_raises_fpe('overflow', lambda a,b:a/b, bx16, sx16)
            assert_raises_fpe('overflow', lambda a,b:a/b, bx16, sy16)
            assert_raises_fpe('overflow', lambda a,b:a/b, by16, sx16)
            assert_raises_fpe('overflow', lambda a,b:a/b, by16, sy16)
            assert_raises_fpe('overflow', lambda a,b:a+b,
                                             float16(65504), float16(17))
            assert_raises_fpe('overflow', lambda a,b:a-b,
                                             float16(-65504), float16(17))
            assert_raises_fpe('overflow', np.nextafter, float16(65504), float16(np.inf))
            assert_raises_fpe('overflow', np.nextafter, float16(-65504), float16(-np.inf))
            assert_raises_fpe('overflow', np.spacing, float16(65504))

            # Invalid value errors
            assert_raises_fpe('invalid', np.divide, float16(np.inf), float16(np.inf))
            assert_raises_fpe('invalid', np.spacing, float16(np.inf))
            assert_raises_fpe('invalid', np.spacing, float16(np.nan))
            assert_raises_fpe('invalid', np.nextafter, float16(np.inf), float16(0))
            assert_raises_fpe('invalid', np.nextafter, float16(-np.inf), float16(0))
            assert_raises_fpe('invalid', np.nextafter, float16(0), float16(np.nan))

            # These should not raise
            float16(65472)+float16(32)
            float16(2**-13)/float16(2)
            float16(2**-14)/float16(2**10)
            np.spacing(float16(-65504))
            np.nextafter(float16(65504), float16(-np.inf))
            np.nextafter(float16(-65504), float16(np.inf))
            float16(2**-14)/float16(2**10)
            float16(-2**-14)/float16(2**10)
            float16(2**-14+2**-23)/float16(2)
            float16(-2**-14-2**-23)/float16(2)
        finally:
            np.seterr(**oldsettings)

    def test_half_array_interface(self):
        """Test that half is compatible with __array_interface__"""
        class Dummy:
            pass

        a = np.ones((1,), dtype=float16)
        b = Dummy()
        b.__array_interface__ = a.__array_interface__
        c = np.array(b)
        assert_(c.dtype == float16)
        assert_equal(a, c)


if __name__ == "__main__":
    run_module_suite()
